Fans were upset after queuing for hours in some places.
Photograph: Jeff Roberson/AP

A McDonald’s public relations stunt has ended in chaos and acrimony after the fast food chain promised fans of the TV show Rick and Morty a limited edition, long-out-of-production Szechuan dipping sauce and then swiftly ran out.

Police were called to at least one outlet after people in queues for the sauce began getting angry and chanting “we want sauce”.

Fans of Rick and Morty, a hugely popular US science fiction cartoon that riffs off the Back to the Future films, descended on McDonald’s restaurants in cities across the US on Saturday after the chain announced it would be selling a limited run of a long out-of-production Szechuan dipping sauce that is referenced in the show’s third season.